Method of making conductor splices



Jan. 2, 1951 J. o. HAMILTON 2,536,173

METHOD OF MAKING CUNDUCTQR SPLICES Filed Oct. 6, 1947 i 2 Sheerls-Sheet1 o N K an w E c N l-l II n 3 1 III X X X i I s INVENTOR J.O. HAMILTONATTORNEV Jan. 2, 1951 J o HAMILTON 2,536,173

METHOD OF MAKING CONDUCTOR SPLICES Filed 00+ 3, 1947 2 Sheets-Sheet 2 JO. HAMILTON y A TTORNE pound.

Patented Jan. 2, 1951 METHOD OF MAKING CONDUCTOR SPLICES James 0.Hamilton, Dundalk, Md., assignor to Western Electric Company,Incorporated, New York, N. Y., a corporation of New York ApplicationOctober 6, 1947, Serial No. 778,237

2 Claims. (Cl. 154-222) This invention relates to methods of makingconductor splices, and more particularly to methods of making flexibleconductor splices.

In the manufacture of covered conductors, such as conductors having aplurality of insulated conductors therein and a jacket of weatherproofing material enclosing the insulated conductors, it is often necessaryto splice conductor lengths together. In order to accomplish this, theconductors of conductor lengths must be connected electrically, and, insome known methods of con necting the conductors of the conductorlengths, it is necessary to remove the insulation from the ends oftheconductors, and to join the conductors by brazing, welding or othersuitable methods. It is then necessary to insulate the bared portions ofthe conductors one from another with unvulcanized, vulcanizableinsulating material, to vulcanize the insulating material on the baredportions of the conductors, to place a quantity of jacketing compoundover the insulating material on the spliced portions of the conductors,and then to vulcanize the jacketing com- Such a series of moldingoperations keeps the cost of such splicing high, and, hitherto, therehas been no successful method of molding the jacketing compound and theinsulating compound in a single molding operation.

An object of the invention is to provide new and improved methods ofmaking conductor splices.

A method illustrating certain features of the invention comprisesenclosing a core of plastic material ina high tensile strength, highmelting point sleeve, placing a mass of plastic material around thesleeve, and applying heat and pressure to the mass of plastic materialto mold simultaneously it and the core.

A complete understanding of the invention may be obtained from thefollowing detailed description of a method of making conductor splicesforming a specific embodiment thereof, when read in conjunction with theappended drawing, in which:

Fig. 1 is a plan view of the ends of two conductor lengths to bespliced;

Fig. 2 is a fragmentary perspective view of a partially completed spliceillustrating certain features of the invention;

Fig. 3 is an enlarged, sectional view of a completed splice;

Fig. 4 is an enlarged, vertical section taken along line 44 of Fig. 3,and

Fig. 5 is an enlarged, sectional view of the completed splice.

Referring now in detail to the drawing, a conductor length I0 to bespliced to a conductor length II consists of two conductors I2 and I3enclosed and separated in a covering I4 composed of a vulcanizedinsulating compound, such as a compound including polymerized butadieneand styrene as its vulcanizable constituent, and a braid I5 of steelstrands served in one direction and cotton strands served in a directionopposite thereto, encloses the covering of insulating material toprovide mechanical strength and electrical protection for the conductorlength. A weatherproofing jacket I6 encloses the braid I5 and iscomposed of a vulcanized jacketing compound, such as a compoundincluding a polymerized chloroprene as its essential constituent. Theconductor length I I is identical with the conductor length I0 andincludes a pair of conductors 22 and 23 which are separated one fromanother and are enclosed in a covering 24 composed of a vulcanizedinsulating compound. A mixed cotton and steel braid 25 encloses thecovering 24, and a vulcanized jacket 26 encloses the braid 25.

In the splicing operation the end portions of the Jackets I6 and 26 areremoved from the conductor lengths I0 and II, respectively. Portions ofthe braids I5 and 25 are removed from the coverings I4 and 24,respectively, and the coverings I4 and 24 are removed from theconductors I2 and I3, and 22 and 23, respectively, so that theconductors l2 and I3 may be brazed to the conductors 22 and 23.respectively. The end portions of the braids l5 and 25 are lashed downtightly upon the coverings I4 and 24 by lashings 30 and 3I (Fig. 1),respectively. A braided sleeve 32 is slipped over the end of one of thecable lengths I0 and II, and the conductors I2 and I3 are brazed to theconductors 22 and 23. A block 40 (Fig. 2) composed of either vulcanizedor unvulcanized, vulcanizable insulating compound of substantially thesame composition as the coverings I4 and 24 is positioned between thebared portions of the conductors I2, I3, 22 and 23 and extends from oneend of the covering I4 to the near end of the covering 24. The block 40is rectangular in cross-section. The depth of the block, which is thedimension of the crosssection of the block perpendicular to the plane inwhich the conductor I2, I3, 22 and 23 lie, is at least as great as thatof the sum of the width of the block, which is the dimension of thiscrosssection in the plane of the conductors, and twice the diameter ofthe conductors. The length of ,strip 4| compresses the rectangular blockand embeds the conductors l2, I3, 22 and 23 in the edges of the block 40so that substantially no air is included therein. However, the block issufficiently wide that the conductors |2 and 22 are spaced sufficientlyfar apart from the conductors l3 and 23 for insulating purposes.Furthermore, since the depth of the block is greater than the widththereof, the strip 4| tends to compress the block more in directionsparallel to the depth thereof than in directions parallel to the widththereof. Hence, the internal pressure of the block keeps the conductorsapart. A strip 42 composed of high tensile strength material, such as astrip formed of glass fibers, is wrapped under tension tightly aroundthe strip 4|, and encloses this strip. The wrapped strip 42 forms a tubeor container around the strip 4| and has a melting point 'suflicientlyhigh to prevent it from melting or softening at the pressures and thetemperatures of vulcanization.

The braided sleeve 32 then is positioned over the strip 42 so as tooverlap the ends of the braids l5 and 25, and the braided sleeve ispulled taut so that it fits closely around the strip 42 and upon thebraids l5 and 25. Lashing wires 45-45 then are applied to the sleeve 32,starting at the center of the sleeve and continued to the ends of thesleeve to lash it down tightly over the portions of the splice enclosedtherein and to take out all the slack of the sleeve 32. The sleeve 32acts as a mechanical barrier over the elements of the splice enclosedtherein, and also serves to connect the braids l5 and 25 mechanically sothat the elements of the splice enclosed within the sleeve 32 areprotected from tensile forces applied to the conductor lengths. Thesleeve also connects the steel wires in the braids electrically.

A covering composed of an unvulcanized, vulcanizable jacketing compoundof substantially the same composition as that of the jackets l6 and 26then is placed over the ends of the jackets and the portions of theconductor lengths i0 and H therebetween. The covering 50 and theportions of the conductor lengths enclosed therein then are placedbetween a pair of heated semielliptical mold sections and 62 whichsubject the splice therebetween to heat and pressure to mold thecovering 50 into an elliptical shape and to vulcanize it, and tosimultaneously form the block 40 and the sleeve 4| into the shape of anellipse and to vulcanize this material. During the molding operation,the sleeve formed by the strip 42 does not melt or soften, and keeps thesleeve 4| and the block 40 from flattening out too much and fromintermixing with the sleeve 50 of jacketing material, but permitstransmission of heat and pressure to the sleeve 4| and the block 40 sothat these elements are vulcanized.

The above-described method of splicing flexible conductor lengths servesto insure adequate spacing of conductors of the conductor lengths sothat they are properly insulated one from another, forms an insulatingcovering around and between the conductors and a jacket around theinsulating covering in a manner in which both the inlll) sulatingcovering and the Jacket may be molded and vulcanized in a single moldingoperation without losing the identity of either the insulatinsulatingmaterial and a jacket of weatherproofing material enclosing theinsulating material, which comprises baring the end portions of theconductors of two such conductor lengths, connecting the ends of onepair 0f the conductors to the ends of the other pair of conductors,placing between the bare portions of the conductors a filler and spacerblock of vulcanizable insulating material having a depth at least asgreat as the width of the block plus the diameters of the conductors,wrapping a strip of insulating material tightly around the bare portionsof the conductor and the filler block therebetween, and applying heat tothe resulting splice to vulcanize the insulating material andsimultaneously exerting pressure on the splice in such a direction thatthe greatest pressure is exerted depthwise on the block, whereby theblock tends to force the bared portions of the conductors apart.

2. The method of splicing conductor lengths or which each includes apair of parallel conductors enclosed and separated from one another byinsulating material and a jacket of weatherproofing material enclosingthe insulating material, which comprises baring the end portions of theconductors of two such conductor lengths, brazing the ends of one pai ofthe conductors to the ends of the other pair of conductors, placingbetween the bare portions of the joined conductors a filler and spacerblock of vulcanizable insulating material having a depth at least asgreat as the width of the block plus the diameters of the conductors,wrapping a strip of insulating material tightly around the bare portionsof the conductor and the filler block therebetween, wrapping a tape ofhigh tensile strength, glass fibers around the strip of insulatingmaterial, enclosing the tape with a mass of unvulcanized, vulcanizablejacketing compound, and simultaneously heating the composite structureto vulcanize the vulcanizable materials and applying.

pressure thereto in such a direction as to apply the greatest pressureon the block depthwise thereof, whereby the internal pressure on theblock keeps the conductors separated.

JAMES O. HAMILTON.

REFERENCES crrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,698,704 Middleton et al Jan. 8,1929 2,105,567 Webb Jan. 18, 1938 2,119,393 Lewis et al May 31, 19382,156,772 Seeley May 2, 1939 2,186,793 Wodtke Jan. 9, 1940 2,264,439Guyatt Dec. 2, 1941 2,403,816 Martin July 9, 1946 2,435,284 Lodge Feb..-2, 1948 FOREIGN PATENTS Number Country Date 421,073 Great Britain July10, 1934 533,532 Great Britain Feb. 14, 1941 542,397 Great Britain Jan.7, 1942

